Modeling and simulation of the supercritical CO2 extraction of vegetable oils

Supercritical Fluid Extraction of Fucoxanthin from the Diatom Phaeodactylum tricornutum and Biogas Production through Anaerobic Digestion

Phaeodactylum tricornutum is the marine diatom best known for high-value compounds that are useful in aquaculture and food area. In this study, fucoxanthin was first extracted from the diatom using supercritical fluid extraction (SFE) and then using the extracted diatom-like substrate to produce bioenergy through anaerobic digestion (AD) processes. Factors such as temperature (30 °C and 50 °C), pressure (20, 30, and 40 MPa), and ethanol (co-solvent concentration from 10% to 50% v/v) were optimized for improving the yield, purity, and recovery of fucoxanthin extracted using SFE. The highest yield (24.41% w/w) was obtained at 30 MPa, 30 °C, and 30% ethanol but the highest fucoxanthin purity and recovery (85.03mg/g extract and 66.60% w/w, respectively) were obtained at 30 MPa, 30 °C, and 40%ethanol. Furthermore, ethanol as a factor had the most significant effect on the overall process of SFE. Subsequently, P.tricornutum biomass and SFE-extracted diatom were used as substrates for biogas production through AD. The effect of fucoxanthin was studied on the yield of AD, which resulted in 77.15 ± 3.85 LSTP CH4/kg volatile solids (VS) and 56.66 ± 1.90 LSTP CH4/kg VS for the whole diatom and the extracted P.tricornutum, respectively. Therefore, P.tricornutuman can be considered a potential source of fucoxanthin and methane and both productions will contribute to the sustainability of the algae-biorefinery processes.

Numerical Simulation on Supercritical CO2 Fluid Dynamics in a Hollow Fiber Membrane Contactor

This research answers the following question: What is the fluid dynamic behavior of a supercritical fluid (SCF) inside a membrane module? At this time, there is very little or no reported information that can provide an answer to this question. The research studies related to the themes of supercritical CO2 (SC-CO2), hollow fiber membrane contactors (HFMCs), and numerical simulations have mainly reported on 2D simulations, but in this work, 3D profiles are presented. Simulations were performed based on the experimental results and other simulations, using the geometry of a commercial module. The results were mainly based on the different operating conditions and geometric dimensions. A mesh study was performed to ensure the mesh non-dependence of the results presented here. It was observed that the velocity profile developed at 10 mm from the wall of the supercritical CO2 entrance pipe. A profile equilibrium around the fiber close to the entrance of the module was achieved in the experimental hollow fiber membrane contactor when compared to the case of the commercial hollow fiber membrane contactor. The results of this research provided a visualization of the boundary layer, which did not cover the entire fiber length. Finally, the results of this paper are interesting for technical applications and contribute to our understanding of the hydrodynamics of SCFs.